Die casting mold inlet means



I Aug. 29, 1967 LAUTERJUNG 3,333,299

DIE CASTING MOLD INLET MEANS Filed Feb. 5, 1965 United States Patent 5 Claims. of. 164-339) The present invention relates to a mold for die casting aluminum, especially aluminum cylinder heads for motor vehicles. With molds of this type it has frequently been noticed that waste results from the formation of shrink holes, which fact is particularly inconvenient in connection with mass production.

Numerous tests have provided that the formation of shrink holes in connection with die casting or chill casting can be avoided to a considerable extent by preventing the aluminum in the casting bridge and the gate from cooling too fast.

It is, therefore, an object of the present invention to provide means in connection with die casting of aluglllllllm, which will overcome the above-mentioned drawac s.

It is another object of this invention to provide means in connection with the die casting of aluminum, which will prevent the aluminum in the casting bridge and the gate from cooling too fast.

It is also an object of this invention to provide means in connection with the die casting of aluminum, which will bring about a heat accumulation adjacent the casting bridge and the gate.

These and other objects and advtanges of the invention will appear more clearly from the following specification in connection with the accompanying drawing in which FIG. 1 is a section through a mold head according to the invention for use in connection with the die casting of aluminum.

FIG. 2 illustrates the dot-dash line encircled portion of FIG. 1 on a larger scale than that of FIG. 1.

The too fast cooling of the aluminum in the casting bridge and/or the pouring gate of a die casting mold is in conformity with the present invention avoided by providing the casting bridge and/or the gate with means which will prevent the aluminum in said casting bridge and gate from emanating its heat too fast toward the outside. When the cast metal in the casting bridge and the gate remains liquid for a longer period of time than was the case heretofore, the aluminum in said casting bridge and gate will be able to flow into the mold proper while the cast work piece is solidifying so that in this way the formation of shrink holes will be prevented.

In order to obtain heat accumulation for the purpose of the present invention, a sleeve or bushing may be inserted into the casting bridge in such a way that an annular gap will be formed between the outer periphery of the bushing and the wall of a corresponding bore in the casting bridge. This gap, and more specifically the air in said gap, acts as a heat barrier for the heat which tends to radiate outwardly, thereby producing the desired heat accumulation. In a similar manner, one or more funnelshaped bushings may be inserted into the pouring gate. Also in this way a too strong heat radiation toward the outside will be prevented in a simple manner and thereby a too fast solidification of the casting material.

The inserted gate bushings also furnish the possibility of providing constrictions directly above the surface of the cast work piece. These constrictions will enable the cast work piece when it is removed from the mold, easily to break oif from the ingates, thereby saving the working step of removing the ingate.

Referring more. specifically to the drawing, the mold not shown in the drawing is arranged on a casting bridge 1 which latter is provided with bores 2 through which bolts may be introduced so that the entire mold can in a manner known per se be turned within the casting machine. This casting bridge is provided with a casting opening 3. Below casting bridge 1 there is provided a pouring gate 4. The-cylinder head 5 to be cast is shown in the drawing while the other mold parts have been omitted.

In order to obtain a heat accumulation of the cast aluminum, according to the present invention, a bushing 6 is inserted into the casting opening 3 of casting bridge 1. The outer circumference of this bushing 6 is slightly less than the inner diameter of the casting opening 3 so that an air gap 7 is formed between these parts 3 and 6. This air gap prevents the heat from radiating outwardly too fast so that the aluminum within the birdge will remain hot considerably longer than was the case heretofore.

In the arrangement shown in the drawing, the gate 4 has inserted thereinto two bushings 8 and 9. As will be seen from the drawing, an air gap 9a is provided between the outer circumferential surface of bushings 8 and 9 and the inner surface of gate 4. This air gap 9a has the same function as air gap 7, namely to form a heat barrier and to allow heat accumulation of the material in said gate.

As will also be evident from the drawing, inserts 8 and 9 are at their passages for the aluminum provided with annular protrusions 10 and 11 for forming a constriction in the ingates. It will thus be obvious that when removing cylinder head 5 form the mold, the ingates will tear off at said constrictions so that no special operation for breaking the ingates off will be necessary.

It is, of course, to be understood that the present invention is, by no means, limited to the particular arrangement shown in the drawing but also comprises any modifications within the scope of the appended claims.

What I claim is:

1. In combination for use in connection with die casting aluminum, especially aluminum cylinder heads for motor vehicles: a first member forming a casting bridge and having a casting opening, a second member forming a pouring gate and being arranged adjacent said first member, and tubular insert means adapted to receive molten aluminum to be die cast and arranged in one of said members and confining therewith an annular air gap for forming a heat barrier to slow down the cooling oif of molten aluminum in said insert means.

2. An arrangement according to claim 1, in which said insert means is inserted in said casting opening of said casting bridge.

3. An arrangement according to claim 1, in which said insert means is inserted in said gate.

4. An arrangement according to claim 3, in which said insert means comprises a plurality of inserts.

5. In combination for use in connection with die casting aluminum, especially aluminum cylinder heads for motor vehicles: a casting bridge having a casting opening, a gate arranged adjacent said casting bridge for communication with said opening, and insert means adapted to receive molten aluminum to be die cast and arranged in said gate and having the outer peripheral wall thereof forming an air gap with the respective adjacent inner surface of said gate, said insert means having passage means therethrough for the aluminum to be cast and having protruding means protruding into said passage means and forming therein a constriction with regard to both the following and preceding wider portions of said passage means.

(References on following page) 3 4 References Cited 3,077,636 2/ 1963 Peters 18--3O 3,137,904 6 /1964 Steinman et a1 22-68 UNITED STATES PATENTS 2,254,119 8/1941 Lester 22--68 X I. SPENCER OVERHOLSER, Primary Examiner.

2,911,680 10/1959 Kelly 18- 0 5 R. S. ANNEAR, Assistant Examiner. 

1. IN COMBINATION FOR USE IN CONNECTION WITH DIE CASTING ALUMINUM, ESPECIALLY ALUMINUM CYLINDER HEADS FOR MOTOR VEHICLES: A FIRST MEMBER FORMING A CASTING BRIDGE AND HAVING A CASTING OPENING, A SECOND MEMBER FORMING A POURING GATE AND BEING ARRANGED ADJACENT SAID FIRST MEMBER, AND TUBULAR INSERT MEANS ADAPTED TO RECEIVE MOLTEN ALUMINUM TO BE DIE CAST AND ARRANGED IN ONE OF SAID MEMBERS AND CONFINING THEREWITH AN ANNULAR AIR GAS FOR FORMING A HEAT BARRIER TO SLOW DOWN THE COOLING OFF OF MOLTEN ALUMINUM IN SAID INSERT MEANS. 